The present invention relates to a rope wedge clamp of the type used for securing a cable or rope to an elevator car. More particularly, the present invention relates to a guard bracket for insuring the retention of clamping engagement of the elevator rope, even during periods of operation of the elevator car when slack cable conditions may be present.
In the past, ropes used in elevators have been secured by the use of babbitt and resin socket techniques. While such securement is generally adequate there are a number of drawbacks to this method. One drawback includes the lack of any means for adjustment of ropes once secured by this method. Also, there are safety problems inherent when using molten babbit in this method.
In recent years, the use of rope wedge clamps has become an increasingly popular alternative in such installations. Use of wedge clamps offer a number of advantages over previous rope termination and securement techniques. Some of these advantages include the ease of installation and adjustment provided by wedge clamps. Such wedge clamps also save in costs of labor versus the prior art methods due to easier installation and adjustment. Wedge clamps operate by securing the elevator rope between opposed angled walls of the wedge clamp and a tear drop shaped wedge around which the cable is wound. The wedge acts to cam the rope against the walls of the wedge clamp during tensioning of the ropes. Such wedge clamps are designed to meet or exceed the relevant requirements for rope connections in elevator installations.
While such wedge clamps have been extremely advantageous and cost effective in the securement of ropes to elevator car structures and the like, the wedge clamps rely on tension on the rope to provide secure engagement of the rope in the wedge clamp. Under certain conditions the rope may slacken reducing tension on the wedge clamp assembly which in a very small minority of cases may cause some slippage in the rope engaged in the wedge clamp. For instance, at times the elevator cars may be out of adjustment such that they "bottom out" or "top out" on either the bottom or the top of the elevator shaft. At these times they may be slack in the rope which may loosen the wedge clamp enough to cause the rope to slip around the wedge. This may cause enough slippage to require readjustment of the cable in the assembly. In other cases such as in a free spool test procedure, the elevator car is dropped by allowing the drive mechanism to "free-spool". Under the free-spool condition emergency brakes engage the elevator car which again produces slack in the ropes. Because in some areas such testing is mandatory at yearly intervals, readjustment of the ropes is often necessary after completion of the test. Thus, in certain situations it is desirable to provide a guard against such disengagement of the wedge in the clamp, which could cause rope slippage.
Therefore, it is a goal in the art to provide a simple inexpensive guard and method which would lessen the chance of rope slippage in such wedge clamps.